ref_sales/sessions/... - Reference Trends

When checking the performance of your Amazon business for a certain time-frame, the Performance feature will allow you to see a reference trend for an additional time-frame. This can either be the period prior to the currently viewed period ("Pre-sequence") or the exact same time-frame from last year.

As an example for the Pre-sequence: If you are looking at the Performance between October 11 and October 20 2016, the reference trend will show you your performance between October 1 and October 10.

"Last year" will then simply show you the Performance between October 11 and October 20 in 2015.